Osteoporosis is a serious public health problem faced by an aging US population. In past decades, there has been significant progress, as well as controversy, in the diagnosis and treatment of osteoporosis. Until recently, bone screening was inaccurate and fracture risk was difficult to calculate. A new diagnostic technique of measuring bone mineral density (BMD) for diagnosis and monitoring the course of treatment (assessment) of osteoporosis and other bone diseases is proposed. The simple and robust measurements of small-angle forward-to-backward scattering and small angle forward scattering-to-transmitted radiation, based on the use of the conventional Coherent to Compton Scattering Ratio (CCSR), can offer a high quality in-vivo measurement of BMD by overcoming prior CCSR limitations, such as high radiation dosage, high system cost and long examining time. Among radiological and other bone diagnostic technologies, CCSR is considered to be a superior and more sensitive method for BMD determination without the need for a case by case calibration. It also has several advantages over the current gold standard technology, Dual-energy X-ray Absorptiometry (DEXA). CCSR is unique in that it provides a quantitative and direct determination of volumetric BMD (in mg/cm3), the "true" density, while the areal BMD (in mg/cm2) that is obtained from DEXA, yields a highly uncertain volumetric density. Another important advantage of CCSR is that it has been accurately applied to trabecular bone in-vivo to yield Trabecular Bone Mineral Density (TBMD) which can be difficult to isolate from cortical bone in some applications of DEXA. Since trabecular bone is the most metabolically active component of the skeleton and can limit bone strength in serious fractures such as those of the hip and spine, the determination of volumetric TBMD is crucial for diagnosis and monitoring of the treatment of osteoporosis and other metabolic bone diseases. Despite the potential and promise of CCSR, it has only been applied in-vivo to the calcaneus using an obsolete configuration. The new approach used in this proposal, will demonstrate that a CCSR-based device is not only highly sensitive and accurate, but also clinically practical and useful to meet the current and future demands of osteoporosis assessment and management. [unreadable] [unreadable] [unreadable]